EGCG诱导人视网膜色素上皮细胞凋亡作用的研究

目的:探讨表没食子儿茶素没食子酸酯(EGCG)对人视网膜色素上皮细胞(ARPE-19)凋亡的影响及其机制。方法:体外培养ARPE-19,分别采用0、40、80、160μg/mL EGCG处理。处理预定时间后分别用hoechst 33258染色法检测细胞凋亡形态学变化;流式细胞仪检测细胞凋亡率;实时荧光定量RT-PCR和Western blotting检测细胞凋亡相关因子B淋巴细胞瘤-2基因(bcl-2)、BCL2-Associated X的蛋白质(Bax)、胱天蛋白酶-3(caspase-3)和p53的表达。结果:hoechst 33258染色结果发现ARPE-19随着EGCG药物浓度的增加,凋亡细胞数量逐渐增多,可见明显的凋亡小体;流式细胞仪结果显示随着EGCG药物浓度的升高,凋亡率逐渐增高,40、80、160μg/mL凋亡率分别为4.95%±0.071%、11.75%±0.075%和21.25%±0.919%与对照组(2.8%±1.556%)相比有差异(P<0.01),呈现出药物浓度依赖性;实时荧光定量PCR和Western blot结果表明EGCG能明显上调凋亡促进因子Bax、caspase-3和p53的mRNA和蛋白表达,同时下调凋亡抑制因子bcl-2的表达,均呈现浓度依赖性。结论:EGCG能明显诱导ARPE-19发生凋亡,其机制与抑制bcl-2的表达,增强Bax、caspase-3和p53的表达有关。

Synergistic impacts of rifampicin and doxorubicin against thioacetamide-induced hepatocellular carcinoma in rats

Background and aims:Combination therapy is a promising new strategy that has been proposed to increase the efficacy of cancer treatment.We aimed to investigate the anti-cancer activity of rifampicin monotherapy and its combination with doxorubicin against hepatocellular carcinoma(HCC).Materials and methods:The in vitro half maximal inhibitory concentration(IC50)and selectivity index(SI)of the drugs under investigation against HepG2 and human lung fibroblast(WI38)cell lines were determined.For the in vivo experiment,male Sprague-Dawley albino rats were injected with thioacetamide at 200 mg/kg twice a week for 90 days;HCC development was confirmed histopathologically.Following HCC induction,the rats were treated with intraperitoneal doxorubicin,rifampicin,or their combination for 45 or 90 days.After sacrifice,the livers were examined histopathologically.The levels of aminotransferases,albumin,bilirubin,malondialdehyde,superoxide dismutase(SOD),catalase(CAT),total antioxidant capacity(TAC),and nitric oxide were measured by spectrophotometry.Alphafetoprotein,cancer antigen 19-9,tumor necrosis factor-alpha,interleukin-6,Bcl-2-associated X protein,caspase 3,caspase 8,and p53 were estimated using ELISA.Results:In vitro,the combination of doxorubicin and rifampicin showed the highest SI of 3.43.In vivo,among the measured markers,the levels of TAC,CAT,SOD,and p53 decreased(P<0.001)and the rest of the measured marker levels increased(P<0.001)in the HCC-bearing rats;after treatment in all groups,all these changes improved toward normal in a time-dependent manner.The combination of doxorubicin and rifampicin optimized the effects of the two individual drugs and exerted the best antioxidant effects.Conclusions:In general,compared with rifampicin or doxorubicin alone,combination therapy has favorable outcomes.Based on our results,the combination of rifampicin and doxorubicin might be applicable for HCC chemotherapy.

Spinal cord decompression reduces rat neural cell apoptosis secondary to spinal cord injury

Objective： To determine whether spinal cord decompression plays a role in neural cell apoptosis after spinal cord injury. Study design： We used an animal model of compressive spinal cord injury with incomplete paraparesis to evaluate neural cell apoptosis after decompression. Apoptosis and cellular damage were assessed by staining with terminal deoxynucleotidyl transferase （TdT）-mediated deoxyuridine triphosphate nick-end labelling （TUNEL） and immunostaining for caspase-3, Bcl-2 and Bax. Methods： Experiments were conducted in male Sprague-Dawley rats （n-78） weighing 300-400 g. The spinal cord was compressed posteriorly at T10 level using a custom-made screw for 6 h, 24 h or continuously, followed by decompression by removal of the screw. The rats were sacrificed on Day I or 3 or in Week 1 or 4 post-decompression. The spinal cord was removed en bloc and examined at lesion site, rostral site and caudal site （7.5 mm away from the lesion）. Results： The numbers of TUNEL-positive cells were significantly lower at the site of decompression on Day 1, and also at the rostral and caudal sites between Day 3 and Week 4 post-decompression, compared with the persistently compressed group. The numbers of cells between Day 1 and Week 4 were immunoreactive to caspase-3 and B-cell lymphoma-2 （Bcl-2）-associated X-protein （Bax）, but not to Bcl-2, correlated with those of TUNEL-positive cells. Conclusion： Our results suggest that decompression reduces neural cell apoptosis following spinal cord injury.

木犀草素对小鼠T淋巴细胞体外增殖及凋亡的作用

目的：研究木犀草素对小鼠T淋巴细胞体外增殖及凋亡作用的影响。方法：设置刀豆蛋白A（Con A）组和空白组,设置3个木犀草素药物组,终质量浓度分别为2.5,5,10 mg·L-1,细胞毒性活性检测-8（CCK-8）法检测各组细胞增殖情况,末端脱氧核苷酸转移酶介导的d UTP缺口末端标记测定法（TUNEL）和Annexin V-FITC/PI双染法检测各组细胞凋亡情况,蛋白免疫印迹法（Western blot）检测各组细胞凋亡通路蛋白B淋巴细胞瘤-2（B-cell lymphoma-2,Bcl-2）,Bcl-2相关X蛋白（Bcl-2-associated X protein,Bax）表达水平。结果：CCK-8实验结果显示3个木犀草素药物组细胞数明显低于Con A组和空白组（P〈0.01）,差异有统计学意义。TUNEL实验结果显示,Con A组的凋亡细胞数量显著低于3个木犀草素药物组（P〈0.01）,差异有统计学意义。流式细胞仪检测结果显示3个木犀草素药物组的细胞凋亡率显著高于Con A组和空白组（P〈0.01）,细胞凋亡率随着药物浓度增加而增高,呈明显的量-效关系。Western blot检测结果显示,2.5,5 mg·L-1木犀草素药物组中Bcl-2表达量高于对照组,Bax表达量低于对照组;10 mg·L-1药物组中Bcl-2表达量低于对照组,Bax表达量高于对照组。结论：2.5,5,10 mg·L-1木犀草素能够抑制T淋巴细胞增殖,能够诱导T淋巴细胞凋亡,10 mg·L-1木犀草素可能主要通过下调Bcl-2,上调Bax影响线粒体凋亡通路诱导细胞凋亡,2.5,5 mg·L-1木犀草素可能通过其他通路诱导细胞凋亡。